1. Field of the Invention
The present invention relates to liquid spray compressors. More particularly, the present invention relates to a liquid spray compressor in which cooling liquid is sprayed into a vessel containing gasses or vapors to be compressed, thereby displacing the gas and simultaneously absorbing a significant amount of the heat of compression.
2. Description of the Prior Art
Compressors with liquid injection for cooling or sealing are well known. For example, U.S. Pat. No. 2,025,142 (Zahn et al) shows a cooling system for a gas compressor in which a spray of cold water is injected into the compressor to cool the gas during compression. The device employs a positive displacement device to compress the gas. Consequently, it requires precision machined pistons and cylinders, which require significant manufacturing time, skill and expense to create. Furthermore, the packing is a source of leakage and friction.
U.S. Pat. No. 2,042,991 (Harris, Jr.) discloses a method and apparatus for producing vapor saturation in which liquid is injected into a compressor during the compression stroke. The apparatus relies on a precision machined piston and cylinder to displace the vapor. The presence of the sprayed liquids in this machine causes problems. In particular, the sprayed liquid can wash away lubricants or oils. Additionally, during the cycle, all of the volume of the cylinder may become filled with liquid. If a discharge valve is closed or if a discharge line is blocked while the piston is displacing the volume, "Hydraulic lock" will occur. Extremely high pressure will result, causing catastrophic failure of the apparatus. The device also wastes energy by spraying the liquid at high pressure.
A compressor utilizing water as a spray into the compression cylinder to cool air that is being compressed to thereby absorb heat is shown in U.S. Pat. No. 2,404,660 (Rouleau), and suffers from the same drawbacks as the Harris and Zahn et al devices.
Rouleau also teaches a gas compressor in U.S. Pat. No. 2,420,098 where some of the compressed gas is used to force a cooling spray into a piston and cylinder compressor. Due to the design of the Rouleau compressor, a volume of gas equal to the volume of cooling liquid is wasted, thereby negating much if not all of the thermodynamic benefit of cooling during compression.
Another compressor is disclosed in U.S. Pat. No. 3,105,630 (Lowler) in which oil or other liquid is injected into the compression chambers of the compressor for cooling, lubricating and sealing purposes. While the Lowler design provides some benefit of direct contact between the cooling liquid and the gas undergoing compression, and avoids "Hydraulic lock," it still requires precision positive displacement elements and considerable manufacturing costs, as well as achieving less than optimum cooling.
U.S. Pat. No. 3,482,768 (Cirrincione) and U.S. Pat. No. 4,273,514 (Shore) illustrate common system for coolant flow to a rotary positive displacement compressor. As such they suffer from the same drawbacks discussed previously, specifically, the need for positive displacement elements which must be manufactured to precise tolerances, requiring considerable manufacturing time and thereby being costly to make.